Control of electrotherapeutic apparatus



July 4, 1967 w, KENDALL 3,329,148

CONTROL OF ELECTROTHERAPEUTIC APPARATUS Filed Sept. 21, 1965 [Na/EN we.1.00M DEA/IS KENDALL 19 True/v5 Y5,

United States Patent 3,329,148 CONTROL OF ELECTROTHERAPEUTIC APPARATUSWilliam Denis Kendall, Los Angeles, Calif., assignor to DynapowerSystems Corporation of California, Santa Monica, Calif., a corporationof California Filed Sept. 21, 1965, Ser. No. 488,977 3 Claims. (Cl.128-422) This invention relates generally to electrotherapeuticapparatus, and more particularly concerns improvements in circuitry fortransmitting high power pulsed radiation and the control thereof.

Major objects of the invention include provision for improved control ofpulsed radiation transmission to enable the operator of the equipment toobtain higher power output and better matching of the equipment to theload represented by the patient, and simplification of the circuitry andcontrols. In this regard, it has been thought necessary in the past toprovide a variable capacitor in a secondary coil tank circuit at thetreatment head, with a manual control at the head; however, such anarrangement has disadvantages which are overcome by the presentinvention.

The above objects may be realized in accordance with the inventionthrough the provision in electrotherapeutic apparatus of a powerradiating head including first means operable to efiect transmission ofpulsed high frequency radiation for treatment of a patient, said meansincluding inductively coupled primary and secondary coils and acondenser electrically connected with the secondary coil to form a tankcircuit, input means to supply pulsed high frequency energy, a networkcoupled to the output of the input means, a coaxial cable having acenter conductor coupling the output of the network to the primary coil,and the network having a capacitor that is controllable to adjustablymatch the output impedance characteristic of the input means to theinput impedance characteristic of the coaxial cable when a patient isundergoing treatment, thereby to optimize the electromagnetic energyoutput of the head. Typically, the network comprises a pi-network or lowpass filter, a console contains the input means and network and theconsole has a control panel, and a manual control at the control panelhas operative connection to the controllable capacitor. Also, the headtypically may include a housing carrying an indicator inductivelycoupled to at least one of the coils to indicate visually to an observerthe strength of the field associated with the inductive coupling, andthe condenser in the housing has fixed capacitance.

These and other objects and advantages of the invention, as well as thedetails of illustrative embodiments, will be more fully understood fromthe following detailed description of the drawings, in which:

FIG. 1 is a schematic showing of the inventive combination;

FIG. 2 shows the wave form head;

FIG. 3 is an external elevation showing the console, control panel andthe arm supported head;

FIG. 4 is a section taken through the control panel and console; and

FIG. 5 is a section taken through the power radiating head.

In the drawings, a power radiating head is indicated generally at 10,and it includes first means operable to effect transmission of pulsedhigh frequency radiation for treatment of a patients anatomy 11 placeddirectly in front of the head. Such a means includes inductively coupledprimary and secondary coils 12 and 13, the secondary coil typicallyhaving three or four turns and transmitted to the power 3,329,143Patented July 4, 1967 the primary coil a single turn, and a condenser 14electrically connected with the secondary coil to form a tank circuit.The coils and condenser are shown as located within a drum-shapedmetallic head shell 15 having an insulative cover plate 16, and thecondenser has an insulative mount at 17.

Indicated at 18 in FIG. 1 is an input means to supply pulsed highfrequency energy. As an illustration of this, reference is made to FIG.2 showing the sequence of like pulses 21, each of which is made up of ahigh frequency signal burst having a selected amplitude 22, and havingintervals 23 therebetween, these having predetermined relationship.Typically, the signal frequency will be 27.12 megacycles, or some otherfixed value, and the interval 23 will be variable, as for example instepwise relation. Also the amplitude equal to one-half the dimension 22will be variable in stepwise relation. The time interval 23 maytypically be varied so as to provide between about and 5,200 pulses persecond in order to increase or decrease the intensity of treatment givento the patient. Apparatus described in US. Patent 3,127,- 895 is usableto provide waveform seen in FIG. 2.

A network is coupled to the output of the input means, one such networkbeing indicated generally at 25 in FIG. 1 and comprising anunsymmetrical pi-net- Work or low pass filter having variable capacitors26 and 27 and an inductance 28 connected as shown. There is also acoaxial cable 29 having a grounded sheath 30 and a center conductor 31,the latter being connected to one terminal of the primary coil 12. Theopposite terminal of the coil 12 is grounded as by connected to thesheath 30 or metallic shell 15. In this regard, no controls are neededat the head for adjusting any electrical impedance elements containedwithin the shell 15.

Capacitor 27 of the network 25 is controllable as by a manual control 40on a control panel 41 that is part of the console 42. The latter carriesan articulated arm 43 supplied with adjustable joints and swivels topermit universal movement of the head 10. FIG. 4 shows the manualcontrol knob 40 having shaft or link connection at 45 to the rotaryplates of capacitor 27 located within the console cabinet.

Capacitor 27 is controllable to adjustably match the output impedancethat is characteristic of the input means 18 to the input impedance thatis characteristic of the coaxial cable 29 when a patient is undergoingtreatment, thereby to optimize energy output of the head 10 fortransmission to the patient. In this regard, the input impedancecharacteristic of the coaxial cable is that which is seen by the network25 looking into the cable, keeping in mind that the cable, head elements12, 13 and 14 and the patient 11 present a load having an impedance thatis seen by the network 25 looking into the cable. The impedance of thatload varies somewhat with the patients anatomy presented to the head,and the user of the equipment may easily and to best advantage match theimpedance of the load to the impedance of the input means 18 byadjusting the knob 40 at the control panel 41, for optimum energytransfer. This result is different from an adjustment of the capacitor14 in the head, since the latter adjustment tends to vary the resonantfrequency of the tank circuit to offset it from 27.12 megacycles. Thepresent circuit keeps the tank circuit resonant at 27.12 megacycles andat the some time enables optimum energy transfer, for therapeuticbenefit.

An indicator glow lamp 50 is mounted on the head, and has a coil 51inductively coupled to at least one of the coils 12 and 13 so as toindicate visually to an observer the increase or decrease in strength ofthe field associated with the inductive coupling of coils 12 and 13,which reflects the increase or decrease in energy 3 transfer to the headas controlled by adjusting knob 40 on the control panel.

I claim:

1. In electrotherapeutic apparatus, a power radiating head includingfirst means operable to effect transmission of pulsed high frequencyradiation for treatment of a patient, said means including inductivelycoupled primary and secondary coils and a non-adjustable capacitancecondenser electrically connected with the secondary coil to form a tankcircuit, input means to supply pulsed high frequency energy in themegacycle range, a network coupled to the output of said input means, acoaxial cable having a center conductor coupling the output of thenetwork to the primary coil, said network having a variable capacitorthat is controllable to adjustably match the output impedance that ischaracteristic of said input means to the input impedance that ischaracteristic of said coaxial cable when a patient is undergoingtreatment, thereby to optimize the electromagnetic energy output of saidhead, a console remote from said head and containing said input meansand network and having a control panel, and a manual control at saidpanel and having operative connection to said controllable capacitor.

2. The combination of claim 1 in which said network comprises api-network, an articulated arm interconnecting the console and head,said cable extending to said head outside but adjacent said arm, saidcable center conductor electrically connecting said controllablecapacitor with said primary coil.

3. The combination of claim 2 in which said head includes a housing, andincluding an indicator on the housing and having a coil in the housingand inductively coupled to at least one of said primary and secondarycoils to indicate visually to an observer the strength of the fieldassociated wit-h said inductive coupling.

References Cited UNITED STATES PATENTS 3,043,310 7/1962 Milinowski128-422 3,127,895 4/1964 Kendall 61'. al. 12 8422 3,181,535 5/1965MilinOWSki 128'-4Z2 3,183,912 5/1965 Mogilner 128421 FOREIGN PATENTS819,994 9/1959 Great Britain.

RICHARD A. GAUDET, Primary Examiner.

W. E. KAMM, Assistant Examiner.

1. IN ELECTROTHERAPEUTIC APPARATUS, A POWER RADIATING HEAD INCLUDINGFIRST MEANS OPERABLE TO EFFECT TRANSMISSION OF PULSED HIGH FREQUENCYRADIATION FOR TREATMENT OF A PATIENT, SAID MEANS INCLUDING INDUCTIVELYCOUPLED PRIMARY AND SECONDARY COILS AND A NON-ADJUSTABLE CAPACITANCECONDENSER ELECTRICALLY CONNECTED WITH THE SECONDARY COIL TO FORM A TANKCIRCUIT, INPUT MEANS TO SUPPLY PULSED HIGH FREQUENCY ENERGY IN THEMEGACYCLE RANGE, A NETWORK COUPLED TO THE OUTPUT OF SAID INPUT MEANS, ACOAXIAL CABLE HAVING A CENTER CONDUCTOR COUPLING THE OUTPUT OF THENETWORK TO THE PRIMARY COIL, SAID NETWORK HAVING A VARIABLE CAPACITORTHAT IS CONTROLLABLE TO ADJUSTABLY MATCH THE OUTPUT IMPEDANCE THAT ISCHARACTERISTIC OF SAID INPUT MEANS TO THE INPUT IMPEDANCE THAT ISCHARACTERISTIC OF SAID COAXIAL CABLE WHEN A PATIENT IS UNDERGOINGTREATMENT, THEREBY TO OPTIMIZE THE ELECTROMAGNETIC ENERGY OUTPUT OF SAIDHEAD, A CONSOLE REMOTE FROM SAID HEAD AND CONTAINING SAID INPUT MEANSAND NETWORK AND HAVING A CONTROL PANEL, AND A MANUAL CONTROL AT SAIDPANEL AND HAVING OPERATIVE CONNECTION TO SAID CONTROLLABLE CAPACITOR.